Heteroatom doping
of carbon networks may introduce active functional
groups on the surface of the material, induce electron density changes
that alter the polarity of the carbon surface, promote the formation
of binding sites for molecules or ions, or make the surface catalytically
active for different reactions, among many other alterations. Thus,
it is no surprise that heteroatom doping has become a well-established
strategy to enhance the performance of carbon-based materials for
applications ranging from water remediation and gas sorption to energy
storage and conversion. Although oxygen functionalization is sometimes
inevitable (i.e., many carbon precursors contain oxygen functionalities),
its participation in carbon materials performance is often overlooked
on behalf of other heteroatoms (mainly nitrogen). In this Mini-review,
we summarize recent and relevant publications on the effect that oxygen
functionalization has on carbonaceous materials performance in different
electrochemical applications and some strategies to introduce such
functionalization purposely. Our aim is to revert the current tendency
to overlook it and raise the attention of the materials science community
on the benefits of using oxygen functionalization in many state-of-the-art
applications.
Acetic anhydride
(AA) is usually considered a stable molecule but
is shown here to be able to polymerize in closed reactors to a cross-linked
polyketone condensate. By using this chemistry, it was possible to
copolymerize AA with l-histidine, which gives a nitrogen-doped
functional nanoporous polymer that can act as an acid–base
heterogeneous catalyst. The polymer acidic and basic sites were screened
by running an acetal hydrolysis Knoevenagel condensation reaction
cascade to optimize catalyst synthesis. Furthermore, it was possible
to catalyze CO2 cycloaddition to epoxides to the corresponding
cyclic carbonate with complete conversion without cocatalysts.
Materials dictate carbon neutral industrial chemical processes. Visible‐light photoelectrocatalysts from abundant resources will play a key role in exploiting solar irradiation. Anionic doping via pre‐organization of precursors and further co‐polymerization creates tuneable semiconductors. Triazole derivative‐purpald, an unexplored precursor with sulfur (S) container, combined in different initial ratios with melamine during one solid‐state polycondensation with two thermal steps yields hybrid S‐doped carbon nitrides (C3N4). The series of S‐doped/C3N4‐based materials show enhanced optical, electronic, structural, textural, and morphological properties and exhibit higher performance in organic benzylamine photooxidation, oxygen evolution, and similar energy storage (capacitor brief investigation). 50M‐50P exhibits the highest photooxidation conversion (84 ± 3%) of benzylamine to imine at 535 nm – green light for 48 h, due to a discrete shoulder (≈700) nm, high sulfur content, preservation of crystal size, new intraband energy states, structural defects by layer distortion, and 10–16 nm pores with arbitrary depth. This work innovates by studying the concomitant relationships between: 1) the precursor decomposition while C3N4 is formed, 2) the insertion of S impurities, 3) the S‐doped C3N4 property‐activity relationships, and 4) combinatorial surface, bulk, structural, optical, and electronic characterization analysis. This work contributes to the development of disordered long‐visible‐light photocatalysts for solar energy conversion and storage.
In this study, we demonstrate the tuning of the oxygen reduction reaction (ORR) by iron/iron oxide nanoparticle grafted laser-patterned nitrogen-doped carbon (LP-NC) electrodes. Depending on the preparation route, i.e. addition...
Novel high performing materials will dictate the pace of reinventing industrial chemical processes to attain desired carbon neutrality targets. Regarding the urgency of exploiting solar irradiation long range visible-light photoelectrocatalysts from abundant resources will play a key role in the aforementioned effort. Anionic doping via co-polymerization and pre-organization of precursors results in tuneable and extrinsic semiconductors, making this a highly attractive methodology. Triazole derivative-purpald, an unexplored precursor but sulfur (S) container, combined with melamine during one solid-state polycondensation reaction with two thermal steps leads to S-doped carbon nitrides (C3N4). The series of S-doped/C3N4-based materials demonstrated enhanced optical, electronic, structural, geometric, textural, and morphological properties and exhibited higher performance in organic benzylamine photooxidation, oxygen evolution, and similar storing energy (capacitor brief investigation) than references. Among the five composites, 50M-50P exhibited the highest photooxidation conversion yield (84±3%) of benzylamine to imine at 535 nm – green light for 48h, due to an extra discrete shoulder reaching ~700 nm, an unusual high sulfur content, preservation of crystal size, new intraband energy states, rare deep structural defects by layer distortion, hydrophobic surface, low porosity, and 10-16 nm pores. An in-depth analysis of S doping was investigated coupling x-ray photoelectron spectroscopy, transmission electron microscope, and elemental analysis, providing insights on bonds, distribution, and surface/bulk content. This work contributes to the development of amorphous photocatalysts with long-visible-light range for solar energy conversion and storage.
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